Device and method for separating retired solar cells

Abstract

The invention discloses a device and a method for separating retired solar cells, and belongs to the technical field of retired solar cell recovery. The device comprises a pressure tank, an electric furnace and a motor, a cover is arranged on one side of the pressure tank, a deflation valve is arranged on the cover, a temperature sensor is arranged on a pressure tank body, a pressure gauge and a connecting rod are arranged on the other side of the pressure tank, the connecting rod is connected with the motor, the motor is arranged in a device box, and a motor rotating speed adjusting knob is arranged on the device box; the electric furnace is arranged below the pressure tank; an electric furnace power switch, an electric power adjusting knob and a thermometer are arranged on the electric furnace; the method for separating the retired solar cell by using the device comprises the following steps of: pretreating the solar cell, putting the pretreated solar cell into the pressure tank, turning on the switch, and adjusting relevant parameters through the electric furnace and each knob of the device box to separate the solar cell. The method has the advantages of greenness, high efficiency, low cost, no harmful gas emission and the like.

Description

Technical Field

[0001] The invention relates to a device and a method for separating retired solar cells, belonging to the technical field of recycling retired solar cells. Background Art

[0002] The demand for low carbon emissions and the energy crisis have driven the rapid development of the global photovoltaic industry. In 2023, the global solar photovoltaic installed capacity will increase by 345.5GW, and the cumulative installed capacity will reach 1.42TW. It is expected to reach 10Tw by 2030 and 30-80Tw by 2050. However, as the global large-scale photovoltaic deployment continues, the challenge of how to deal with a large number of photovoltaic modules at the end of their service life of about 25 to 30 years is emerging. Photovoltaic modules are far from waste, but valuable urban minerals.

[0003] Crystalline silicon solar cells are widely used due to their mature technology, with crystalline silicon modules accounting for more than 95% of the market share. Ag and Si account for 47% and 11% of their economic value, respectively. In addition to Ag and Si, crystalline silicon solar modules also contain Al, Cu, Sn, Pb and glass, which account for about 65% of the production cost of photovoltaic modules. In addition, small amounts of heavy metals such as Sn, Pb and organic matter may pose an environmental threat if not properly managed. People have been working on developing efficient and clean methods for recycling retired photovoltaic modules.

[0004] With the enrichment of photovoltaic module types and the continuous improvement of photovoltaic module preparation technology, the development prospects of photovoltaic module application market will be broader. The development of photovoltaic modules faces more diversified requirements. The market and related industries not only require the improvement of the conversion efficiency of photovoltaic modules, but also require the continuous reduction of raw materials and manufacturing costs, and the reduction of energy consumption. The second-generation retired photovoltaic modules are welcomed by the industry and the market for their advantages such as less material consumption, more mature preparation technology, low preparation energy consumption, lighter weight, higher photoelectric conversion efficiency, and lower attenuation rate. The second-generation retired photovoltaic modules, represented by retired CIGS solar cells, had an output of 1.3GW in 2015 and 1.9GW in 2017, and are expected to reach 4.37GW by 2023. At the same time, the market share of retired solar cells is expected to increase from 16.7% in 2030 to 50% in 2040. Due to the expected life of 20 to 30 years, a large number of abandoned retired solar cells will be generated in the near future. In the next 5 to 10 years, a large number of retired solar cells will be scrapped, and the number will increase rapidly over time.

[0005] Therefore, it is of great significance to recycle scrapped retired solar cells. At present, there are many methods for recycling retired solar cells, mainly including: pyrometallurgical recycling, wet recycling, combined pyrometallurgical and wet recycling, physical recycling, etc., but there are few studies on efficient and clean interlayer separation of retired solar cells. If the retired solar cells can be separated from each other before recycling, it will greatly reduce the difficulty of recycling, reduce recycling time, improve recycling efficiency, reduce recycling energy consumption, reduce chemical reagent consumption, and reduce harmful gas emissions.

[0006] Therefore, how to carry out the interlayer separation of retired solar cells in a green, efficient and low-cost manner has become an urgent problem to be solved by those skilled in the art. Summary of the invention

[0007] In view of the deficiencies and shortcomings of the existing interlayer separation technology for retired solar cells, one of the purposes of the present invention is to provide a method for separating retired solar cells, which specifically includes the following steps:

[0008] (1) Curl the retired solar cells to a certain curvature, the curvature range is 25m -1 ~50m -1 , cut into battery cells.

[0009] (2) Place the cut battery cells into a container filled with deionized water for ultrasonic treatment.

[0010] (3) placing the battery cells processed in step (2) into a pressure tank, adding deionized water and heating the cells, and when the temperature and pressure reach a certain value, instantly releasing the pressure in the sealed container to separate the battery cells and obtain a separation product.

[0011] (4) Collecting the separated product obtained in step (3) and drying it to obtain a separated product.

[0012] Preferably, the retired solar cells in step (1) include: retired CIGS solar cells, whose structure from top to bottom is encapsulation PET, EVA film, battery layer, stainless steel backplane, EVA film, encapsulation PET; the cutting size is 1×1cm~16×16cm; retired crystalline silicon solar cells, whose structure from top to bottom is glass, EVA film, battery layer, TPT backplane; the cutting size is 1×1cm~4×4cm.

[0013] Preferably, the curvature range in step (1) is 30m -1 ~50m -1 .

[0014] Preferably, the ultrasonic treatment time in step (2) is 10 to 120 minutes.

[0015] Preferably, in step (3), the amount of deionized water added to each gram of the battery cell is 1-20 ml; the pressure is controlled to be 2-4 MPa, and the temperature is controlled to be 100-300°C.

[0016] Preferably, the drying conditions in step (4) are vacuum at 50° C. and drying for 40 min.

[0017] Another object of the present invention is to provide a device for separating retired solar cells, the device comprising a pressure tank and an electric furnace, the pressure tank being placed above the electric furnace to facilitate heating of the pressure tank by the electric furnace, and a vent valve being installed on the pressure tank to instantly release the pressure in the pressure tank.

[0018] Preferably, the electric furnace wall is provided with an electric furnace power switch, an electric power adjustment knob, and a temperature meter; the electric furnace power switch is used to control the opening and closing of the electric furnace, and the electric power adjustment knob is used to adjust the power of the electric furnace.

[0019] Preferably, a lid is connected to one side of the pressure tank, an air release valve is installed on the lid, a temperature sensor is installed on the side wall inside the pressure tank to monitor the temperature inside the pressure tank, and a pressure gauge is provided on the pressure tank to monitor the pressure inside the pressure tank.

[0020] Preferably, the pressure tank can be connected to the motor via a connecting rod, the motor is fixedly installed in the device box, the speed of the motor is adjusted by adjusting the speed adjustment knob, and the motor can rotate the pressure tank via the connecting rod so that the pressure tank is heated evenly.

[0021] Principle of the present invention:

[0022] (1) The curvature of retired solar cells is regulated so that gaps are created between the layers to facilitate the diffusion of deionized water between the layers during the ultrasonic process.

[0023] (2) The treated retired solar cells are placed in a pressure tank and deionized water is added. As the temperature of the pressure tank increases, the temperature of the deionized water continues to rise, accelerating its diffusion between the layers of the battery. As the temperature further increases, the deionized water in the gaps between the layers of the battery vaporizes. In this process, the deionized water changes from liquid to gas, and its volume expands, which further increases the gaps between the layers and weakens the bonding between the layers.

[0024] (3) During the process of increasing the temperature of the pressure tank, due to the different thermal expansion properties of the layers of the retired battery, the encapsulation PET / glass, encapsulation EVA, battery cells and stainless steel substrate / TPT backplane experience varying degrees of volume contraction or expansion, which further expands the gaps between the layers and further weakens the adhesion between the layers.

[0025] (4) When the vent valve is opened and the pressure tank is opened, the pressure inside the pressure tank drops from a high pressure state to a normal pressure state, and the water vapor between the layers of the battery cells also drops from a high pressure state to a normal pressure state. According to the ideal gas state equation PV = nRT, the amount of water vapor between the layers of the battery cells will not change, and the temperature will not change much. The sudden drop in pressure will cause the volume of the water vapor to expand instantly. The combined principles (1)(2)(3)(4) cause the layers of the retired batteries to separate.

[0026] Beneficial effects of the present invention:

[0027] (1) The present invention can orderly separate the layers of retired solar cells within 3 to 5 minutes, thereby achieving efficient interlayer separation of retired solar cells.

[0028] (2) While efficiently separating the decommissioned solar cells between layers, only deionized water is introduced as the medium without any other chemical additives. No pollutants are generated during the entire process, thus achieving the goal of green environmental protection.

[0029] (3) The present invention enables the valuable metals in retired solar cells to be effectively enriched. The enrichment of valuable metals in retired solar cells after interlayer separation by this method is increased by more than 3.5 times.

[0030] (4) The present invention exposes the cell layers in retired solar cells, which greatly facilitates the subsequent recovery of valuable metals and greatly improves the leaching rate of valuable metals. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of a method for separating retired solar cells.

[0032] Figure 2 A schematic diagram of the structure of a device for separating retired solar cells.

[0033] In the figure: 1. cover; 2. air release valve; 3. temperature sensor; 4. pressure tank; 5. pressure gauge; 6. connecting rod; 7. device box; 8. motor; 9. speed adjustment knob; 10. temperature gauge; 11. electric furnace; 12. electric power adjustment knob; 13. electric furnace power switch.

[0034] Figure 3 This is a picture of the PET-cell, stainless steel backplane, encapsulation EVA, and encapsulation PET obtained by separating retired CIGS solar cells in Example 1.

[0035] Figure 4 This is a picture of the PET-cell, stainless steel backplane, encapsulation EVA, and encapsulation PET obtained by separating retired CIGS solar cells in Example 2.

[0036] Figure 5 This is a picture of the PET-cell, stainless steel backplane, encapsulation EVA, and encapsulation PET obtained by separating retired CIGS solar cells in Example 3.

[0037] Figure 6 This is a picture of the glass, battery cells, encapsulation EVA, and TPT backplane obtained by separating retired crystalline silicon solar cells in Example 4.

[0038] Figure 7 This is a picture of the glass, battery cells, encapsulation EVA, and TPT backplane obtained by separating retired crystalline silicon solar cells in Example 5. DETAILED DESCRIPTION

[0039] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following embodiments are only simple examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0040] A device for separating retired solar cells, such as Figure 2 As shown, the device mainly includes three parts: a pressure tank 4, an electric furnace 11 and a motor 8; an electric furnace power switch 13 and an electric power adjustment knob 12 are provided on the wall of the electric furnace 11, the electric furnace power switch 13 is used to control the opening and closing of the electric furnace 11, and the electric power adjustment knob 12 is used to adjust the power of the electric furnace; the pressure tank 4 is placed above the electric furnace so that the electric furnace can heat the pressure tank 4, a temperature sensor 3 is installed on the side wall inside the pressure tank 4 to monitor the temperature inside the pressure tank 4, a cover 1 is installed on one side of the pressure tank 4, a vent valve 2 is fixedly connected to the cover 1, a pressure gauge 5 and a thermometer 10 are installed on the other side of the pressure tank 4 to monitor the pressure and temperature inside the pressure tank 4, the pressure tank 4 is fixedly connected to a connecting rod 6 as a whole, the connecting rod 6 is connected to the motor 8, the motor 8 can drive the pressure tank 4 to rotate through the connecting rod 6, and the motor 8 speed adjustment knob 9 is placed on the device box 7 for installing and fixing the motor 8.

[0041] Example 1

[0042] A method for separating retired solar cells using the device of the present invention, the specific steps are as follows:

[0043] (1) Roll the retired CIGS solar cells to a certain curvature of 50 μm. -1 , cut into 2×2 cm battery pieces and put into a beaker filled with deionized water for 30 minutes of ultrasound.

[0044] (2) Open the lid 1 of the pressure tank 4 and place the battery cells treated in step (2) into the pressure tank 4, add 2 ml of deionized water, close the lid 1, turn on the electric furnace power switch 13 on the electric furnace 11, adjust the power adjustment knob 12 to make the electric furnace power 1000 W, let the electric furnace 11 start to heat the pressure tank 4, adjust the speed adjustment knob 9 to make the speed of the motor 8 100 r / min, the motor 8 can drive the entire pressure tank 4 to rotate through the connecting rod 6, when the device runs for 2 minutes and 40 seconds, the temperature in the pressure tank 4 reaches 225 ° C and the pressure reaches 3 MPa, press the vent valve 2 for instantaneous venting to obtain the product.

[0045] (3) The product collected in step (2) is vacuum dried at a drying temperature of 50° C. for a drying time of 40 min to obtain a product after separation of the layers of the retired solar cell sheets, such as Figure 3 As shown, it includes: PET-battery sheet layer, stainless steel back sheet, EVA, and encapsulated PET. The separation of the stainless steel back sheet makes the battery sheet exposure ratio reach 99.8%, and the enrichment of valuable metals therein is increased by about 3.5 times on average.

[0046] Example 2

[0047] A method for separating retired solar cells using the device of the present invention, the specific steps are as follows:

[0048] (1) Roll the retired CIGS solar cells to a certain curvature of 40 μm. -1 , cut into 2×2 cm battery pieces and put into a beaker filled with deionized water for 40 minutes of ultrasound.

[0049] (2) Open the lid 1 of the pressure tank 4 and place the battery cells treated in step (2) into the pressure tank 4, add 3 ml of deionized water, close the lid 1, turn on the electric furnace power switch 13 on the electric furnace 11, adjust the power adjustment knob 12 to make the electric furnace power 1000 W, let the electric furnace 11 start to heat the pressure tank 4, adjust the speed adjustment knob 9 to make the speed of the motor 8 120 r / min, the motor 8 can drive the entire pressure tank 4 to rotate through the connecting rod 6. When the device runs for 3 minutes, the temperature in the pressure tank 4 reaches 218°C and the pressure reaches 3 MPa, press the vent valve 2 for instantaneous venting to obtain the product.

[0050] (3) The product collected in step (2) is vacuum dried at a drying temperature of 50° C. for a drying time of 40 min to obtain a product after separation of the layers of the retired solar cell sheets, such as Figure 4 As shown, it includes: PET-battery sheet layer, stainless steel back sheet, EVA, and encapsulated PET. The separation of the stainless steel back sheet makes the battery sheet exposure ratio reach 99.7%, and the enrichment of valuable metals therein is increased by about 3.5 times on average.

[0051] Example 3

[0052] A method for separating retired solar cells using the device of the present invention, the specific steps are as follows:

[0053] (1) Roll the retired CIGS solar cells to a certain curvature of 30 μm. -1 , cut into 2×2 cm battery pieces and put into a beaker filled with deionized water for 60 minutes of ultrasound.

[0054] (2) Open the lid 1 of the pressure tank 4 and place the battery cells treated in step (2) into the pressure tank 4, add 5 ml of deionized water, close the lid 1, turn on the electric furnace power switch 13 on the electric furnace 11, adjust the power adjustment knob 12 to make the electric furnace power 1000 W, and let the electric furnace 11 start to heat the pressure tank 4. Adjust the speed adjustment knob 9 to make the speed of the motor 8 150 r / min. The motor 8 can drive the entire pressure tank 4 to rotate through the connecting rod 6. When the device runs for 4 minutes, the temperature in the pressure tank 4 reaches 235°C and the pressure reaches 3 MPa. Press the vent valve 2 to open the instantaneous pressure difference separator.

[0055] (3) The product collected in step (2) is vacuum dried at a drying temperature of 50° C. for a drying time of 40 min to obtain a product after separation of the layers of the retired solar cell sheets, such as Figure 5 As shown, it includes: PET-battery sheet layer, stainless steel back sheet, EVA, and encapsulated PET. The separation of the stainless steel back sheet makes the battery sheet exposure ratio reach 99.1%, and the enrichment of valuable metals therein is increased by about 3.4 times on average.

[0056] Example 4

[0057] A method for separating retired solar cells using the device of the present invention, the specific steps are as follows:

[0058] (1) Curl the retired crystalline silicon solar cells to a certain curvature of 50m -1 , cut into 2×2 cm battery pieces and put into a beaker filled with deionized water for 40 minutes of ultrasound.

[0059] (2) Open the lid 1 of the pressure tank 4 and place the battery cells treated in step (2) into the pressure tank 4, add 4 ml of deionized water, close the lid 1, turn on the electric furnace power switch 13 on the electric furnace 11, adjust the power adjustment knob 12 to make the electric furnace power 1000 W, let the electric furnace 11 start to heat the pressure tank 4, adjust the speed adjustment knob 9 to make the speed of the motor 8 120 r / min, the motor 8 can drive the entire pressure tank 4 to rotate through the connecting rod 6, when the device runs for 4 minutes, the temperature in the pressure tank 4 reaches 261 ° C and the pressure reaches 6 MPa, press the vent valve 2 for instantaneous venting to obtain the product.

[0060] (3) The product collected in step (2) is vacuum dried at a drying temperature of 50° C. for a drying time of 40 min to obtain a product after separation of the layers of the retired solar cell sheets, such as Figure 6 As shown, it includes: glass, EVA, battery cell, and TPT back panel.

[0061] Example 5

[0062] A method for separating retired solar cells using the device of the present invention, the specific steps are as follows:

[0063] (1) Curl the retired crystalline silicon solar cells to a certain curvature of 50m -1 , cut into 3×3 cm battery pieces and put into a beaker filled with deionized water for 40 minutes of ultrasound.

[0064] (2) Open the lid 1 of the pressure tank 4 and place the battery cells treated in step (2) into the pressure tank 4, add 5 ml of deionized water, close the lid 1, turn on the electric furnace power switch 13 on the electric furnace 11, adjust the power adjustment knob 12 to make the electric furnace power 1000 W, let the electric furnace 11 start to heat the pressure tank 4, adjust the speed adjustment knob 9 to make the speed of the motor 8 150 r / min, and the motor 8 can drive the entire pressure tank 4 to rotate through the connecting rod 6. When the device runs for 5 minutes, the temperature in the pressure tank 4 reaches 283°C and the pressure reaches 7 MPa, press the vent valve 2 for instantaneous venting to obtain the product.

[0065] (3) The product collected in step (2) is vacuum dried at a drying temperature of 50° C. for a drying time of 40 min to obtain a product after separation of the layers of the retired solar cell sheets, such as Figure 7 As shown, it includes: glass, EVA, battery cell, and TPT back panel.

[0066] The above is only part of the embodiment of the application, and does not limit the application in any form. Any simple modification, equivalent change and modification made to the above embodiment still falls within the scope of protection of the technical solution of the application.

Claims

1. A method for separating retired solar cells, characterized in that: The specific steps include: (1) Curl the retired solar cells to a certain curvature, the curvature range is 25m -1 ~50m -1 , cut into battery cells; (2) placing the cut battery cells into a container filled with deionized water for ultrasonic treatment; (3) placing the battery cell treated in step (2) into a pressure tank, adding deionized water and heating the cell, and when the temperature and pressure reach a certain value, instantly releasing the pressure in the sealed container to separate the battery cells and obtain a separation product; (4) Collecting the separated product obtained in step (3) and drying it to obtain a separated product.

2. The method for separating retired solar cells according to claim 1, characterized in that: The retired solar cells described in step (1) include: CIGS solar cells, whose structure from top to bottom is encapsulation PET, EVA film, battery layer, stainless steel back plate, EVA film, encapsulation PET; the cutting size is 1×1cm~16×16cm; crystalline silicon solar cells, whose structure from top to bottom is encapsulation glass, EVA film, battery layer, TPT back plate; the cutting size is 1×1cm~4×4cm; other retired solar cells with interlayer structure.

3. The method for separating retired solar cells according to claim 1, characterized in that: The ultrasonic treatment time in step (2) is 10 to 120 minutes.

4. The method for separating retired solar cells according to claim 1, characterized in that: In step (3), the amount of ionized water added is 1-20 ml; the pressure is controlled to be 2-4 MPa, and the temperature is controlled to be 100-300° C.

5. The method for separating retired solar cells according to claim 1, characterized in that: The drying conditions in step (4) are vacuum at 50° C. and drying for 40 min.

6. A device for separating retired solar cells, characterized in that: The device comprises a pressure tank (4) and an electric furnace (11), wherein the pressure tank (4) is placed on the electric furnace (11), and a gas release valve (2) is installed on the pressure tank (4).

7. The device for separating retired solar cells according to claim 6, characterized in that: An electric furnace power switch (13) and an electric power adjustment knob (12) are arranged on the wall of the electric furnace (11).

8. The device for separating retired solar cells according to claim 6, characterized in that: A cover (1) is connected to one side of the pressure tank (4), a venting valve (2) is installed on the cover (1), a temperature sensor (3) is installed on the side wall inside the pressure tank (4), and a pressure gauge (5) and a temperature gauge (10) are also installed on the pressure tank (4).

9. The device for separating retired solar cells according to claim 6, characterized in that: The pressure tank (4) can be connected to the motor (8) via a connecting rod (6), the motor is fixedly installed in the device box (7), and the speed adjustment knob (9) of the motor (8) is placed on the device box (7).

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